This is a proposal to acquire a FACSAriaII flow cytometer/high-speed sorter as an additional state-of- the-art high-speed flow cytometer to increase sorting capacity and add the capability of performing UV laser-based sorting. The rationale for this request rests on the increase in demand from users requiring cell sorting in their NIH-sponsored research, the continued delays in service imposed by our facility due to a shortage for instrument time. These limitations persist even after an extension of operating hours and an additional technician in order to handle those extended hours, and the need to add UV-sorting for user. We are proposing this instrument to be equipped with a UV laser and appropriate optics capabilities to enable major NIH-funded investigators to perform sorting currently not possible using our existing sorter, mainly Hoeschst staining for side populations of stem cells such and/or cell cycle on viable samples. This additional sorter would provide much-needed added capacity to the currently over- booked single DakoCytomation MoFlo sorter at the facility. This well-regarded facility was established over 25 years ago. It is currently staffed by three experienced technicians and monitored by a faculty user committee. The sorting capabilities of this core facility were last upgraded in 2001 with the purchase of the DakoCytomation MoFlo high-speed sorter configured for detection of up to 6 fluorochromes. Many investigators at Wistar and in neighboring institutions routinely use the cell sorting services for their NIH-funded work, with this single MoFlo sorter booked to capacity with waiting times of up to 3-4 weeks to schedule a single sorting appointment. Extended core facility operational hours have been made available since January 2007 yet backlog and delayed progress on NIH-funded work continues. We have now reconfirmed backlog and a lack of sufficient and reliable access to near-by high speed sorting services. Therefore, we propose to upgrade this facility through the purchase of a BD FACSAriaII flow cytometer/high-speed sorter, configured as a special order system with state-of-the art detectors, UV laser and associated optics for detection of side population stem cells stained with Hoechst 33342. PUBLIC HEALTH RELEVANCE: This requested sorting instrument will enable Wistar to extend access of state-of-the-art high-speed sorting in support of multiple NIH-funded projects focused on cellular analysis of transcription, autoimmunity, infectious disease, cancer biology, gene therapy, and vaccine development.